Safety mixer



Aug. 4, 1931- F. L. CRADDOCK 1,817,353

SAFETY MIXER Filed Aug. 28. 1929 [I ll/m, 101

INVENTCR EM 1;. Crwidoulf ATTORN EY Patented Aug. 4,

UNITED STATES mnnmcx L. cmnnocx, on NEW YORK, 11. Y., ASSIGNOB 'ro mxme EQUIPMENT- PATENT, OFFICE COMPANY, INC., 'OF ROCHESTER, NEW YORK, A CORPORATION OI NEW YORK SAFETY MIXER This invention is an improvement on the mixing devices described in my Patent No. 1,703,099, and relates particularly to an improved fire safe mixer of high general efli- -ciency. One object of this invention is to combine in this mixer and improved specialiform of motor, preferably a completelyenclosed and protected motor, with the factors of my mixer as described in my above mentioned patent, so'as to provide a highly efiicient mixer for general use, and in addition, one which can be operated safely for the mixing of inflammable mixes or mixes involving a fire hazard.

Another object of this invention is to provide a motor-driven mixing device with a fan and associated parts designed to draw free air, positioned at least a short distance away 29 from the mixing member and the adjacent spray and fumes created by it, and, also when required to blow emanations from the mix away from the motor, thus promoting its cleanliness, fire safety and cool operation.

Another object is to provide an improved combination of instrumentalities designed to promote cleanliness, safety and efiiciency, which may be applicable to any and all forms of mixers, including the specific embodiment described in the following detailed description of a preferred construction.

Referring to the accompanying drawmg The figure is a side view of my safety mixer in operating position shown partly in section, mounted on a typical tank. It may be observed that the operating mechanism, except the fire safety and motor cooling combination, are much like the correis placed a hemispherical mating casting 11,

sponding parts in my above mentioned patprovided with a slot 13, in which is laced a washer 15, having two downward y extending lugs 1717 to prevent rotating of the washer 15 with respect to the casting 11.

A bolt 19, having its head at the lower end, in a recess in clamp 3, extends upwardly through washer 15 and is provided with a. conventional washer 21 and nut 23.

Thus the clamp 3 and the casting 11 may be adjustably locked in position with respect to each other by the nut 23. This adjustability is equivalent to that of a ball and socket joint and is universal for any practical position of the mixing propeller 25 in the tank 1.

The casting 11 extends as indicated and surrounds the lower portion of a motor 27, to which it is attached by screws 2929, which enter the tapped holes 31-31 found in standard motors of this type.

The casting 11 also extends downwardly to form an outboard bearing which contains a grease impregnated wooden bushing 32 for the hollow portion 33 of the propeller shaft 33--35. Members 33 and 35 are held together by a chuck 100, and wrench jaw grip flats 34 are formed on shaft 33. The field yoke (or, in the case of an alternating current motor, the starter) 101 is provided with conventional end closure members 102 and 104, and, a number of radial cooling flanges 103103 which are surrounded by a cylindrical casing 105, thus forming an air confining pas; sage wherein heat generated in the motor may be transferred to the air contained in the passage.

At an upper extension 107 of the motor shaft 39 there is mounted a centrifugal blower fan 109 surrounded by a casing 111 having several holes 113113 at its central portion and communicating at its lower end with shell 105. The fan thus draws in free air posi-t tioned far enough away from the mixing member to be free of spray or vapor.

When a motor of this improved type is operated in conventional applications other than in my improved mixer it has the advantage of being dustproof, fireproof and self-cooling, but when operated in combination with the other parts of my mixer an additional advantage develops of blowing any emanations of the mix away from the motor 27, tending thus to cool the surface of the mix as well as reducin the fire hazard when the mix is inflammabTe.

A construction such as that, shown in the drawings Where both the cooling air in the motor and the propeller stream of the mixture in the tank are caused to fiow in a direction substantially parallel to the axis of rotation of the motor shaft appears to have advantages of efficiency and convenience as compared to other possible arrangements.

As an additional precaution for use in specially inflammable mixes, I provide a coupling hood 115 which is bolted by bolts 117-117 to casing 111 and carries one end of an exhaust hose 119 the remote end of which draws in fresh air from the outside of the building at the port-hole 121.

The direction of the air circulation through the various above described parts of the apparatus is indicated in the drawing by arrows.

I claim z- 1. A mixer including an electric motor, a mixing shaft provided with a mixing member and a fan actuated by the motor said fan being so arranged as to blow emanations from the mix away from the motor.

2. A mixer including an electric motor, a mixing shaft provided with a mixing member and a fan actuated by the motor said fan being so arranged as to blow emanations from the mix away from and cool the motor.

3. A mixer including an electric motor a mixing shaft provided with a mixing member and a fan actuated by the motor said fan being provided with means to draw air from a remote source of pure air and blow same upon the motor to effect a cooling thereof,

. the air thereby becoming heated, and means to direct such heated air so as to shield the motor from any emanations from a mix thatmay flow toward the motor from the vicinity of said mixing member.

4. A mixer including an electric motor, a mixing shaft provided with a mixing member and a fan actuated by the motor said fan being provided with means to draw air from a remote source of pure air and blow emanations from a mix away from and cool the motor.

5. A mixer including an electric motor, a mixing member actuated by the motor, and blower means, also actuated by the motor, designedto circulate air upon and cool same and also to blow emanations from the mix away from the motor.

6. The combination in a portable mixer of an electric motor having a shaft, a screw propeller mounted thereon and designed to propel a mixture containing liquid in a direction substantially parallel with the axis of said shaft, a fan also mounted upon the shaft and designed to circulate cooling air upon the motor, and cooling ducts associated with the fan designed to conduct said air in the general direction of the propeller.

7. The combination in a portable mixer of an electric motor having a shaft, a screw propeller mounted thereon and designedto propel a mixture containing liquid in a direction substantially parallel with the axis of said shaft, a fan also mounted upon the shaft and designed to circulate cooling air upon the motor, cooling duct means associated with the fan and designed to conduct said air in a general direction substantially parallel with the axis of said shaft and thereby cool the motor.

8. The combination in a portable mixer of an electric motor having a shaft, a screw propeller actuated thereby and designed to propel a mixture containing liquid in a direction substantially parallel with the axis of said shaft, a fan also actuated by the motor and designed to circulate cooling air upon the motor, cooling duct means associated with the fan and designed to conduct said air in a general direction substantially parallel with the axis of said shaft and thereby cool the motor.

FREDERICK L. GRAD-DOCK. 

